1. Field of the Invention
The present invention relates to an electrodeless lighting system and a bulb therefor and particularly, to an electrodeless lighting system and a bulb therefor, capable of emitting light in case of re-lighting.
2. Description of the Background Art
Generally, an electrodeless lighting system is a device for emitting visible rays or ultraviolet rays by applying microwave to an electrodeless lamp, as a microwave generated in a magnetron is transmitted to a resonator though a waveguide and applied to an electrodeless bulb installed inside the resonator and filled material which is filled in the bulb is plasma polymerized. Therefore, the system has longer life span than that of incandescent lamp or fluorescent lamp which is generally used, and has higher lighting effect.
An example of the electrodeless lighting system will be described with reference to FIGS. 1 and 2.
FIG. 1 is a longitudinal cross-sectional view showing a general electrodeless lighting system according to the conventional art and FIG. 2 is a partial cut-away detailed view of a bulb in FIG. 1.
The conventional electrodeless lighting system includes a casing 10, a high voltage generator 20 positioned on the inner front surface of the casing 10 for generating high voltage, a magnetron 30 positioned at a predetermined interval from the high voltage generator 20, for generating microwave by the high voltage generated in the high voltage generator 20, a waveguide 40 fixed on the front surface of the casing 10 and protruded to the outside of the casing 10, for guiding the microwave generated from the magnetron 30, a resonator 50 installed at the front outer side of the casing 10 so that it is connected with the waveguide 40, for resonating the microwave guided through the waveguide 40 and at the same time, preventing leakage of microwave to the outside, a bulb 60 mounted to be capable of rotating inside the resonator 50, for generating light as the filled material is excited by the microwave, and a reflector 80 positioned at the circumference of the bulb 60, for reflecting light which is generated from the bulb 60 to the front.
Also, a fan housing 110 installed at the rear side of the casing 10 so that heat generated in the high voltage generator 20 and magnetron 30 is protected, for sucking external air, a cooling fan 100 positioned in the fan housing 110, for sucking external air and a fan motor 101 for rotating the cooling fan 100, are positioned inside the casing 10.
The bulb 60 is positioned at the outer side of the exit 70 which is formed in the waveguide 40 and as shown in FIG. 2, includes a bulb portion 62 which is formed in a globular shape having a filling space 61 therein, and a bulb stem 63 which is lengthened and formed in a rod shape having a predetermined length at a side of the bulb portion 62. The bulb stem 63 is connected to the rotation shaft 91 passing through the waveguide 40 with reference to FIG. 1. The rotation shaft 91 is connected to a bulb motor 90 which is positioned between the fan housing 110 and the waveguide 40.
Therefore, the rotation shaft 91 is rotated by the operation of the bulb motor 90, the bulb is rotated by rotation of the rotation shaft 91 and accordingly, the bulb 60 is cooled.
In the filling space 61 of the bulb 60, primary emission fills which lead light emission by forming plasma in the operation, such as halogen compounds or sulfur (S), Selenium (Se), and the like, inert gas for forming plasma at the initial stage of light emission, such as argon (Ar), Xenon (Xe), Kripton (Kr) and the like and additives for easing lighting by helping initial discharge or adjusting a spectrum of the generated light, are filled in the bulb.
The operation of the electrodeless lighting system will be described.
Firstly, when a power source is applied, a high voltage is generated in the high voltage generator 20 and a microwave is generated in the magnetron 30 by the high voltage impressed.
The microwave generated in the magnetron 30 is transmitted to the resonator 50 through the waveguide 40 and a strong electric field is distributed in the resonator 50. The material which is filled inside the bulb 60 is discharged by the electric field and at the same time, evaporated, thus to generate plasma.
Namely, the inert gas which is filled in the bulb 60 is discharged by a strong electric field distributed inside the resonator 50 and plasma is formed as the main luminous material is evaporated by heat which is generated by discharge of the inert gas. Then, light is emitted maintaining discharging by the microwave which is continuously supplied to the resonator 50.
Also, light which is emitted is reflected by the reflector 80 and thrown forwards.
Simultaneously, as the bulb 60 is rotated by operating the bulb motor 90, the bulb 60 is cooled and an external air flows to the inside of the casing 10 as the cooling fan 100 is rotated by operating the fan motor 101, thus to cooling the high voltage generator 20 and magnetron 30.
However, the conventional electrodeless lighting system has a disadvantage that re-lighting is not directly conducted but in several tens of seconds or several minutes, if the bulb 60 is re-lit after light-out of the bulb 60 under the lighting condition.
The disadvantage is caused since a sufficient mean free path of an electron having energy which is needed for plasma discharging can not be secured as the pressure of the neutral gas which is filled inside the bulb 60 is too high. Particularly, even though 5% of light efficiency is increased in case of using Xenon (Xe) as the inertia gas than in case of using just argon (Ar), discharging becomes more difficult under the condition of high voltage because of the large collision cross section of Xenon (Xe).
On the other hand, as a conventional method for reducing the time required for lighting, the internal pressure of the bulb 60 can be lowered by cooling by directly blowing a strong wind. However, the conventional method caused problems of an increase in the cost for mounting an additional device for blowing the strong wind, reliability of the additional device, utilization of the circumference of the electrodeless lighting system, and light shading which is discharged by the additional devices.
Therefore, an object of the present invention is to provide an electrodeless lighting system, capable of minimizing the time required for lighting of a bulb.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an electrodeless lighting system, including a waveguide having an outlet which is installed being protruded from the inside of a casing to the outside of the casing, for transmitting a microwave generated in the magnetron, a resonator fixed at the outer side of the outlet of the waveguide, for forming a resonant region in which the microwave is resonated, a bulb for generating light as plasma is generated by an electric field which is formed inside the resonator and a lighting promoting means positioned inside the bulb, for concentrating the electric field so that light is rapidly emitted when the microwave is applied.
Also, the conductive member includes a basic member having a predetermined diameter and length to maintain a physical shape and a conductive layer made by coating a conductive material on the basic member, for concentrating the electric field.
The conductive member of the electrodeless lighting system in accordance with the present invention further includes a protection layer for preventing the conductive member from having a reaction directly with plasma on the conductive layer.
With the electrodeless lighting system in accordance with the present invention, convenience of a user can be achieved and reliability of lighting can be increased, since electric field is concentrated at both ends of the conductive member which is mounted inside the bulb in case of applying a microwave of the bulb by positioning the conductive member in the filling space of the bulb and the bulb can emit light.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.